To obviate the aforementioned deterioration of round roll bales, vary recent proposals have come forth to protect such bales with covering material, such as plastic film. One example of such solution is the subject of prior U.S. Pat. No. 4,173,112 to Meiners, dated Nov. 6, 1979, in which a roll bale is proposed to be wrapped in sheet plastic film by a number of convolutions thereof and then the covering plastic film is severed from a supply roll by a shaped blade having a V-shaped cutting edge. The end of the wrapped film is then glued to the roll or otherwise the roll may be left in a field and permit the weight of the roll to prevent unwrapping of the covering film from the roll bale.
The wrapping art also offers some suggestions as to how a large cylindrical object, such as a roll of paper may be wrapped with a paper sheet, such as proposed in prior U.S. Pat. No. 4,224,782, to Moflag, dated Sept. 30, 1980, but adaptation of the rather complex structure thereof to a baler for round bales appears to be cumbersome and complex.
A German published application, No. 2,705,101, filed Nov. 23, 1978, appears to suggest wrapping a roll bale of agricultural material with a strip of what seems to be plastic material of limited width wound spirally around a roll bale with the edges of the successive convolutions overlapping a limited extent by threading the supply roll transversely across the bale somewhat similarly to the wrapping of binder twine around such a bale, as mentioned above relative to roll balers of earlier years.
The securing of plastic film coverings to roll bales has been a problem which has now led to the proposal to use stretch cling-type plastic film material which has the advantage of the convolutions of such film clinging or adhering to each other when wrapped around an article, such as a roll bale of forage material and this characteristic has the added advantage of automatically attaching the outer end of the wrapped film to the next layer thereof. Providing means to handle and apply such stretch cling-type plastic film requires departure from using the prior types of film wrapping mechanisms referred to above and the present invention has been conceived to utilize such type of plastic film for use in balers for roll bales, details of the structure to accomplish this being described below.